Hexane → 4-(2,2-Dibromovinyl)-4'-pentylbiphenyl

Participants

Reaction Conditions

Reaction Steps

A solution of 15.3 g of tetrabromomethane in 150 ml of methylene chloride was placed at 0° C. in a sulphonation flask under argon gasification and treated within 5 minutes with a solution of 12.1 g of triphenylphosphine in 50 ml of methylene chloride. After completion of the addition, the clear orange reaction solution was stirred at 0° C. for a further 5 minutes and then a solution of 5.80 g of 4-formyl-4'-pentylbiphenyl in 50 ml of methylene chloride was added dropwise within 10 minutes. After stirring at 0° C. for a further 45 minutes, the yellow-orange mixture was poured into 1000 ml of hexane and the precipitate which thereby separated was filtered off (rinsing with hexane). The concentrated filtrate was digested with 400 ml of hexane, left to stand at 0° C. for 18 hours, filtered (rinsing with hexane) and the filtrate was concentrated. Low-pressure chromatography (0.5 bar) of the residue (9.8 g) on silica gel with hexane gave 5.15 g (55%) of 4-(2,2-dibromovinyl)-4'-pentylbiphenyl as colourless crystals (purity 99.1%); m.p. 95° C.

Provenance & Evidence